Climate, Flora, and Fauna

Introduction

Figure 1: Map of Switzerland: Robenhausen is located just east of Zürich.

The climate of Lake Pfäffikon during the Swiss Neolithic had a profound effect on the availability of plants, animals, and other natural resources at Robenhausen and nearby lake dwellings sites. Weather affected growing seasons, while shifts in lake water levels affected the lake dwellers’ ability to use the land and influenced the range of plants and animals living in the area. The often swampy areas around the lakes and, later, rising lake levels helped ensure the preservation of organic material in the archaeological record. A thorough examination of the climate, flora, and fauna of this area gives modern excavators and researchers a clearer picture of the resources and challenges of living on and near the lake during the Swiss Neolithic (Figure 1).

Climate

Temperature, rainfall, plants, and seasonal changes can be examined using a variety of archaeological sources, including changing lake levels, pollen distribution, and isotopic analysis. When combined, this information provides a more complete picture of the climate and environment at the time. Pollen, for example, provides information on plant distribution, temperature, and seasonal changes. Pollen analysis has shown that lake levels were higher during years with more rainfall, resulting in cool summers and short growing seasons. Likewise, lower lake levels occurred during years with less rainfall, warmer summers and longer growing seasons. In addition to indicating the general weather for that year, lake levels also changed due to major climate changes, seasonal shifts, and variations from year to year.

Evidence from lake levels, pollen and other analysis reflects a dramatic climate shift around 3500 BC, from the cooler Atlantic to the milder Sub-Boreal climate. The long, cold Atlantic winters and cool, rainy summers gave way to the generally warmer Sub-Boreal period. The Sub-Boreal climate was accompanied by a decrease in tree populations and lower lake levels, leaving larger areas open for settlements and created a more favorable environment for farming. Despite the increased potential for agriculture, the lake dwellers had a limited impact on their environment, particularly in comparison with the deforestation seen in the archaeological record for later periods.

Animals

In addition to humans, mammals living in the area during the Swiss Neolithic included cattle, dog, wolf, goat, deer, beaver, elk, wild horse, hedgehog, otter, lynx, badger, sheep, squirrel, domesticated pig, wild boar, bear, fox, mice, and a variety of other species. Local birds included duck, goose, golden eagle, grey heron, buzzard, white stork, common wood pigeon, common raven, carrion crow, swan, Arctic gull, kite, and starling. The lakes also contained fish, including carp, pike, perch, and salmon. Evidence has also been found for frogs, toads, and even houseflies.

There are several ways for animals to appear in the archaeological record. Evidence may be direct or indirect. Direct evidence includes bone, antler, horn, or coprolites (fossilized dung); indirect evidence reflects human activities which indicate animal presence, such as fish nets and archery equipment. Fishing is often documented through indirect evidence, because fish bones are rarely preserved in the archaeological record. Tools made of bone, horn, and antler also determine what animals were available and utilized by the lake dwellers.

Plants

Figure 3: MPM Item 10130: Charred wheat and barley grains.

Figure 2: MPM Item 15048:
Hazelnuts from Swiss Lake Dwelling.

Evidence of plants can be found in the form of fruit, seeds, and items such as textiles and tools. While some plants were actively used by the lake dwellers, others simply inhabited the same area. Tree species included fir, maple, birch, pine, elm, oak, and yew. Hazelnuts (Figure 2), cherries, woodland strawberries, apples, plums, blackberries, elderberries, flax, and barley were also present.

Wheat, especially emmer, and millet (Figure 3) were crucial to lake dwelling populations during this time period, although the availability of particular varieties varied by time and location. As such, they can be used to help trace human migrations as well as information and technology dispersal. For example, an increase in emmer consumption around 2400 BC also represents local technological developments. Likewise, the presence of specific wheat varieties north but not north-east of the Alps indicates that these originated in south-west Europe, and an increase in flax (which, along with emmer wheat, is believed to have originated in the east) is accompanied by an increase in loom weights made of clay.

Domestic and Wild Varieties of Plants and Animals

While it can be difficult to differentiate between wild and domestic plants and animals in early archaeological contexts, remains at Swiss Neolithic sites indicate that both were present and played an important role. Lake dwellers exploited wild plants and animals as well as domestic ones. Instead of being a strictly hunter/gather or agricultural society, the lake dwellers shifted between subsistence methods as necessary. This shows not only the effect of local resources on the lake dwellers, but also the effect their settlements had on the local flora and fauna. The population growth which accompanied the shift away from hunter/gatherer strategies put a heavier emphasis on farming and cereal production, despite the continued fluctuation between subsistence methods.

Significance of Floral/Faunal Remains

Robenhausen and other Swiss Neolithic sites are unique for their high level of organic preservation, including worked bone and antler, textiles, fruit, and other foodstuffs. These are often the first things to decay and disappear in the archaeological record. While the charring or burning exhibited by many remains from the site in the MPM Swiss Neolithic collection contributed to their excellent preservation, the lake itself was a far more important factor in the quantities of organic remains found at Robenhausen. Because the lake levels rose soon after the site was abandoned, much of the material from Robenhausen was quickly covered by water and mud, creating a barrier between the fragile organic material and outside air. The oxygen-poor conditions prevented the decomposition which usually destroys organic material. The layer of mud, silt, and water protected many of these items until they were rediscovered in the late 19th century. The preservation of organic material also makes it possible to accurately date these settlements using carbon (C14) dating and dendrochronology, or tree-ring dating.

While modern systematic excavation methods consider unworked bone, antler, plants, and even pollen important, early excavation techniques often missed their significance. In contrast to his contemporaries, Jakob Messikommer’s experience as a farmer helped him to recognize many of these organic remains as a valid venue of scientific inquiry. During his decades of excavations at Robenhausen, items such as apples, grains, wood, bone, antler, and raw materials like bast and flax were kept for identification. Messikommer sent bone and plant samples to Ferdinand Keller, founder and President of the Antiquities Society in Zürich, who in turn sent them to osteologist Ludwig Rütimeyer and botanist Oswald Heer for identification. As Messikommer built a collection of labeled, identified material, he began to make his own identifications based on the initial efforts of these specialists. Messikommer was a pioneer in what has become known as archaeobotany, which has helped modern researchers better understand the plants, animals and environment that were an important part of survival for the Swiss Neolithic lake dwellers.